Nearly mile-wide asteroid with orbiting moon expected to pass by Earth

LOS ANGELES - A nearly mile-wide asteroid that has its own moon is expected to fly safely by Earth on Saturday.

The smaller “asteroid moon” is around a third of mile wide and orbits the space rock named Asteroid 1999 KW4.

The asteroid will clear Earth at a safe distance of around 3.2 million miles, according to NASA.

The 1999 KW4 is a binary system that was discovered on May 20, 1999, hence its name. 

The space rock has an “oblate shape dominated by an equatorial ridge,” NASA said. The Las Cumbres Observatory also said it's “quite a complex shape.”  

“It is slightly squashed at the poles and with a mountain ridge around the equator, which runs all the way around the asteroid. This ridge gives the primary an appearance similar to a walnut or a spinning top,” the observatory said.

The asteroid will be “the target of an extensive observing campaign” supported by NASA's Planetary Defense Coordination office, the agency said. 

Additionally, the observatory reported that the 1999 KW4 is the focus of this year’s International Asteroid Warning Network Campaign “to test Earth’s capability to characterize and prepare for an incoming, potentially hazardous asteroid.” 

“We have to make sure that people understand that this is not about Hollywood. It’s not about movies. This is about ultimately protecting the only planet we know right now to host life, and that is planet Earth,” said Jim Bridenstine, NASA administrator.

Bridenstine spoke during the International Academy of Astronautics Planetary Defense Conference in College Park, Maryland in May, saying that detecting, tracking and studying meteor and other near-Earth objects is a big project NASA has been working on.

He also said every 60 years, a meteor could hit Earth and cause serious damage, which is why the possible threat should be taken more seriously.